Sandfish (Scincus scincus), which is kind of reptile living in desert, can move in sand like swimming. It is thought that since sandfish has a low friction scales, it is able to do that. However, the mechanism of the low friction property of the scales is not yet known. In this study, a micro structure of sandfish’s scales was investigated, and their tribological properties under μN loads were measured. Cuticle-like structure, which is observed on human hairs, appeared on the scales. Detected elements on the scales were O, C, N, and S. Ca and Si, which are elements of hard shells and bones, were not detected. A contact angle of sandfish’s scale was around 90º, and polytetrafluoroethylene (PTFE) and polyimide (PI) had contact angles of approximately 110º and 60º, respectively. However, an adhesion force of sandfish’s scales was lower than those of PTFE and PI. With the exception of a few frictional conditions, a friction force of sandfish’s scales was lower than those of PTFE and PI, which would result from the low adhesion force of sandfish’s scales.
Bipolar-type plasma based ion implantation and deposition (bipolar PBII&D) is a promising surface coating technique for the complex-shaped target surface. In this study, DLC films were prepared by bipolar PBII&D technique to a trench-shaped pattern, and uniformity, structure and mechanical properties of the DLC films on the top, inside wall and bottom surfaces of the trench were evaluated by surface roughness measurements, Raman spectroscopy and nanoindentation hardness tests. As a result, thickness uniformity of the DLC films improves with decreasing negative pulse voltage. On the other hand, the thickness of DLC films on the inside wall of the trench is much smaller than those of the top and bottom surfaces of the trench. The reason for this may be because the conformal ion sheath is not formed in surrounding of the inside wall. For the DLC films on the inside wall, Raman G-peak position shifts to a higher wave number and Full width at half maximum of G-peak 〔FWHM(G)〕decreases to a smaller value compared to those of the films on the top and bottom surfaces. These indicate that the DLC films on the inside wall surface are graphitized, which results in reduction of hardness.